Annular seals are an often used tool in downhole systems. They are particularly useful and indeed indispensable in, for example, hydrocarbon production systems where complexity is the rule and various strata of a particular formation are productive of different types of fluid. Whether all of the fluids accessed by the well are desirable and simply need to be separately managed or desirable and undesirable fluids are accessed simultaneously requiring exclusionary control of unwanted fluids, annular seals consistently play a significant part.
Considering the importance of annular seals, and the potential “cost” of failure of these seals, it might be expected that the materials used for their construction would be robust. This is not generally the case, however, in that elastomers have long been the seal material of choice due to their sealing ability but are not particularly robust. Elastomers are susceptible to degradation from exposure to heat, pressure swings and chemically harsh environmental species. Since all such derogatory factors are plentiful in the downhole environment of a hydrocarbon well, degradation of annular seals is axiomatic and the requirement for repair thereof regular. The art would unequivocally welcome an annular seal that is more resistant to the commonly existing environmental conditions downhole.